Many rifles are used for target shooting. Their accuracy can be measured by one or more of several methods including the resulting group size or by the score achieved when shooting a scoring target. Regardless of the method of measuring, consistency is key to either small groups or high scores. Numerous devices and procedures have been devised to improve accuracy and target shooters go to great lengths to improve accuracy. A current event is shooting at a range of 1,000 yards with the record for such a range being a group size of less than three inches. To achieve such results, the shooter will take extraordinary steps in ensuring consistency to achieve accuracy. For example, cartridges will be precisely hand loaded. The necks of the cases will be turned for concentricity of the neck opening of the case relative to the chamber. The overall length of the cartridge and in particular the position of the ogive relative to the lands of the rifling will also be carefully controlled. The type of powder, the type of primer, etc. will also be extremely precisely controlled for consistency from shot to shot. One of the important factors in achieving extreme accuracy is the position of the bullet relative to the case. To achieve extreme accuracy, the longitudinal axis of the bullet must be aligned with the longitudinal axis of bore of the barrel when positioned in the chamber. The bullet needs to be as perfectly formed as possible with high concentricity between the jacket and the core and should have no nicks or scratches prior to firing. Further the bullet must be consistently seated to position the ogive relative to the lands on the rifling in the rifle bore to control the distance the bullet moves before contacting the lands (this is often times referred to as bullet jump).
A very popular type of rifle for target shooting is the bolt action rifle. Many target rifles are single shot rifles which allow for precise alignment of the cartridge when advancing it into the chamber by manipulation of the bolt. However, many rifles used for competitive or target shooting are not single shot rifles but have a magazine and are so called repeaters. In fact, many shooting events such as silhouette shooting utilize repeaters. In order for a rifle to be versatile, it would be desirable to be able to use it both as a repeater as well as a single shot with single shot mode being used, for example, when bench rest shooting.
Repeating rifles use a magazine for holding multiple cartridges. In order to reduce the magazine height, the cartridges are stacked in a staggered side to side orientation, i.e., their centerlines are on opposite sides of the centerline of the magazine. Such a magazine will typically include a follower with a deck providing support for the bottom cartridge and an elongate rib that projects upwardly from the deck for supporting the second from bottom cartridge and also forcing the cartridges to be positioned in the staggered side-by-side orientation. Thus, when a cartridge is fed from the magazine to the chamber by forward movement of the bolt, the cartridge enters the chamber at a sideways angle (as viewed from the top of the gun) relative to the longitudinal axis of the chamber and the bore of the barrel instead of longitudinally aligned therewith. Sometimes a lot of force is applied to the bolt to assist in locking the bolt lugs and sometimes in seating the cartridge in the chamber. Such out of alignment loading can cause the bullet to become nicked, and/or forced back into the case further or shifted to an angle out of axial alignment with the longitudinal axis of the case neck. All of these factors can adversely affect accuracy. One solution to preventing such problems is to hand feed a cartridge into the chamber and then close the bolt on it in essence making the gun a single shot. However, with the magazine in place (which keeps a cartridge from falling thru the gun stock), the rib on the follower will stop forward movement of the bolt in many rifles to help in, amongst other things, preventing dry firing of the firearm. This requires that the shooter manually depress the follower to allow forward motion of the bolt to lock the cartridge in the chamber for firing. Such manipulation of the magazine is not only inconvenient but can also shift the rifle on the rests affecting accuracy.
Devices have been made for converting a magazine to a single shot. One such device is sold under the name Score High and fits under the inwardly turned lips at the top of the magazine. However, if the magazine is one that has a ribbed follower, such an insert is supported along only one side and will rock from side to side resulting in potential misalignment of the cartridge as discussed above.
An additional problem with some cartridges is that with large bullet sizes, the overall cartridge length exceeds that which will permit the cartridge to fit between the front and back walls of the magazine. This longer length is oftentimes required to provide the optimum spacing of the bullet to the lands for optimum bullet jump. Thus, they cannot be loaded into the magazine. In target shooting, many times a longer bullet is desirable to improve the ballistics coefficient, which can improve accuracy yet they cannot be loaded into the magazine. Thus, the use of a standard magazine to contain cartridges can limit the variety of cartridges useable in the firearm and may prevent the achievement of optimum bullet jump.
There is, thus, a need for an improved firearm with a convertible magazine to improve its versatility in use and potential accuracy.
Among the several objects and features of the present invention may be noted the provision of a firearm that can be utilized both as a single shot and a repeater without requiring major modification to the structure of the firearm. The firearm utilizes a magazine capable of holding multiple cartridges that by the provision of an auxiliary platform may be easily converted to a single shot firearm. The platform permits accurate alignment of the cartridge with the chamber of the barrel as well as the bore to reduce the risk of damage to the bullet and the cartridge when being inserted into the chamber for subsequent firing. The platform has a channel for receiving and guiding the cartridge while holding down the magazine follower to allow the bolt to move forward to advance the cartridge without the bolt catching on the follower. The platform also includes at least one spacer, which may be adjustable, to hold the platform securely in position in the magazine. By use of the removable platform, the firearm may be used both as a repeater when needed and as a single shot when needed.
The invention may be practiced as a retrofit to pre-existing rifles without modifying the rifle and alternately may be incorporated into the rifle as originally manufactured.
Other objects and features will be in part apparent and in part pointed out hereinafter.